Restoration of hypoxia-stimulated glucose uptake in GLUT4-deficient muscles by muscle-specific GLUT4 transgenic complementation

Juleen R. Zierath, Tsu Shuen Tsao, Antine E. Stenbit, Jeffrey W. Ryder, Dana Galuska, Maureen J. Charron

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

To investigate whether GLUT4 is required for exercise/hypoxia-induced glucose uptake, we assessed glucose uptake under hypoxia and normoxia in extensor digitorum longus (EDL) and soleus muscles from GLUT4-deficient mice. In EDL and soleus from wild type control mice, hypoxia increased 2- deoxyglucose uptake 2-3-fold. Conversely, hypoxia did not alter 2- deoxyglucose uptake in either EDL or soleus from either male or female GLUT4- null mice. Next we introduced the fast-twitch skeletal muscle-specific MLC- GLUT4 transgene into GLUT4-null mice to determine whether changes in the metabolic milieu accounted for the lack of hypoxiamediated glucose transport. Transgenic complementation of GLUT4 in EDL was sufficient to restore hypoxiamediated glucose uptake. Soleus muscles from MLCGLUT4-null mice were transgene-negative, and hypoxia-stimulated 2-deoxyglucose uptake was not restored. Although ablation of GLUT4 in EDL did not affect normoxic glycogen levels, restoration of GLUT4 to EDL led to an increase in glycogen under hypoxic conditions. Male GLUT4-null soleus displayed reduced normoxic glycogen stores, but female null soleus contained significantly more glycogen under normoxia and hypoxia. Reduced normoxic levels of ATP and phosphocreatine were measured in male GLUT4-null soleus but not in EDL. However, transgenic complementation of GLUT4 prevented the decrease in hypoxic ATP and phosphocreatine levels noted in male GLUT4-null and control EDL. In conclusion, we have demonstrated that GLUT4 plays an essential role in the regulation of muscle glucose uptake in response to hypoxia. Because hypoxia is a useful model for exercise, our results suggest that stimulation of glucose transport in response to exercise in skeletal muscle is totally dependent upon GLUT4. Furthermore, the compensatory glucose transport system that exists in GLUT4-null soleus muscle is not sensitive to hypoxia/muscle contraction.

Original languageEnglish (US)
Pages (from-to)20910-20915
Number of pages6
JournalJournal of Biological Chemistry
Volume273
Issue number33
DOIs
StatePublished - Aug 14 1998

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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